Micromax Q4202 User manual

Q4202 L2 Service Manual
A) Technical Specifications:
Particular
Remarks
Key Matrix For Flashing
LSK
Chipset
MSM8909
Android Version
Android 6.0
Frequency
1.1GHz
Network Mode
2G/GSM：B 2\3\5\8
3G/WCDMA ：B 1\8
4G/FDD：B3\5\40
Rom
8GB
RAM
1GB
Internal SD Card memory
MB can support up 32GB T card
Expandable Memory
MB can support up 32GB T card
Factory mode code
*#86428#
Good Earpiece volume
32 Ω±15%
Good Loudspeaker volume
8Ω±15%
Good MIC volume
2 Ω±15%
Good Vibrator volume
58Ω

Q4202 L2 Service Manual
Engineering Code
NA
B) CAUTIONS
I. Flashing & Servicing must be undertaken by qualified personnel only.
II. Ensure all work is carried out at an anti-static workstation and that an anti-static wrist strap is worn.
III. Use only approved Tools & components as specified in the parts list.
IV. Ensure all components, modules, screws, and insulators are correctly re-fitted after servicing and
alignment
V. Ensure all cables and wires are repositioned correctly if Handset disassembled
VI. Electrostatic discharge can easily damage the sensitive components of electronic products.
Therefore, Service Centre must adhere the precautions which mentioned above.
C) SERVICE DETAILS
D) SYMPTOMS :
1. Does not power on
LCD+TP
Earphone
connector
Vibrate
I/O
Front
camera
Main
camera
SIM
connector
RF
Antenna
Batt
ery
conn
ector
GSM
Antenna
BWG
ANT
FJ ANT

Q4202 L2 Service Manual
NO.
Description
Reason
Solution
1
NO Power On
Software issue
Update Software
Battery capacity level is too low
Charging the Battery
Power On Key is fail
Change Key
Main PCBA issue
Refer to the L3 maintenance manuals or
change PCBA
2：Display issue/No display
NO.
Description
Reason
Solution
1
LCD+TP
Software issue
Update Software
LCD fail\ TP connection
issue
Change LCD
LCD backlight circuit issue
Refer to the L3 maintenance manuals or Change
PCBA
Side Key FPC
soldering
Power Key
Battery
connector
LCD connector

Q4202 L2 Service Manual
3：Proximity Sensor not working
NO
Description
Reason
Solution
1
Proximity
sensor
Software issue
Download software
Sensor holder is not assembled well
Re-assemble the sensor holder
PCBA fail
Change PCBA/Refer to L3 repair
Inspect the sensor. If it is broken, change with a new one.
4：G-sensor not working
NO
Description
Reason
Solution
1
Proximity
sensor
Software issue
Download software
Sensor holder is not assembled well
Re-assemble the sensor holder
PCBA fail
Change PCBA/Refer to L3 repair
5：Keys not working
NO.
Description
Reason
Solution
P- sensor
G- sensor

Q4202 L2 Service Manual
1
Key is not work
Key fail
Change Key
Key is not assembled well
Re-assemble
PCBA issue
Change PCBA/Refer to L3 repair
6：Charging issue
NO.
Description
Reason
Solution
1
Cannot charge
Adapter fail
Change adapter
2
Have charging icon,
But not charged
Battery fail or Battery
connect fail
Change battery or Change battery connect
FPC fail or FPC connect
fail
Change FPC or FPC connect
PCBA fail
Change PCBA/Refer to L3 repair
S
7：USB port issue
NO.
Description
Reason
Solution
1
Cannot connect
to PC
Data cable is fail
Change data cable
USB connect fail
Change USB connect
Side Key FPC
soldering
Side Key FPC
USB connector
Battery connector
FPC

Q4202 L2 Service Manual
FPC fail or FPC
connect fail
Change FPC or FPC connect
Main PCBA issue
Change main PCBA/Refer to L3 repair
8：Front Camera not working
NO.
Description
Reason
Solution
1
Colored screen when open
front camera
Camera issue
Change camera
Camera connect fail
Change camera connect
PCBA issue
Change PCBA/Refer to L3 repair
2
Cannot turn on front camera
Camera issue
Change camera
Camera connect fail
Change camera connect
PCBA issue
Change PCBA/Refer to L3 repair
9：Rear Camera not working
NO.
Description
Reason
Solution
1
Colored screen when open
front camera
Camera issue
Change camera
Camera connect fail
Change camera connect
PCBA issue
Change PCBA/Refer to L3 repair
2
Cannot turn on front
camera
Camera issue
Change camera
Camera connect fail
Change camera connect
PCBA issue
Change PCBA/Refer to L3 repair
USB connector
Front camera connector
FPC
Battery connector

Q4202 L2 Service Manual
10：Error Playing Video
NO.
Description
Reason
Solution
1
Flash Light
Software issue
Update Software
Flash light fail
Change flash light
PCBA fail
Change PCBA/Refer to L3 repair
11：Vibrator not working
NO.
Description
Reason
Solution
1
Vibrator
Setting issue
Open the vibration function
Soldering issue
Re-soldering vibrator
Soldering issue
Re-soldering Main FPC
Rear camera connector
Flash Light
drive IC
Flash Light

Q4202 L2 Service Manual
Main FPC connect fail
Change Main FPC connect
Moto issue
Change Moto
Main FPC fail
Change Main FPC
Main PCBA issue
Change main PCBA/Refer to L3 repair
12：WiFi/BT /GPS not working
NO.
Description
Reason
Solution
Software issue
Update software
antenna fail
Change antenna
PCBA issue
Change PCBA/Refer to L3 repair
13：RF (SIM) Network issue
NO.
Description
Reason
Solution
1
4G can not
4G did not open
Open the 4G
Main FPC connect
Vibrator soldering
Antenna
connector

Q4202 L2 Service Manual
searchable
Software issue
Update software
34G antenna is fail
Change 4G antenna
RF cable connect issue
Reassemble the RF cable connect
RF Cable fail
Change RF Cable
SUB PCBA issue
Change SUB PCBA
PCBA fail
Change PCBA/Refer to L3 repair
14：FM not working
NO.
Description
Reason
Solution
1
FM is not working
Software issue
Update software
Earphone issue
Change earphone
Earphone connect fail
Change earphone connect
PCBA fail
Change PCBA/Refer to L3 repair
15: Receiver not working
RF cable
connector
Antenna
connector
Ear phone connector

Q4202 L2 Service Manual
NO.
Description
Reason
Solution
1
Receiver
The volume to shut down
Press V +, transferred to the suitable volume
Dust with receiver
Clean receiver
Receiver issue
Change receiver
Volume key issue
Change volume key
PCBA issue
Change PCBA/Refer to L3 repair
16：Earphone not working
NO.
Description
Reason
Solution
1
Single output
from earphone
Earphone issue
Change earphone
Earphone jack smudges
Clean up the earphone jack
Earphone jack pin is weld weak
Strong weld the jack pin
Earphone jack is fail
Change earphone jack
Main PCBA fail
Change main PCBA/Refer to L3 repair
17：MIC not working
NO.
Description
Reason
Solution
1
Mic
Setting issue
Open the vibration function
Soldering issue
Re-soldering Mic
Soldering issue
Re-soldering Main FPC
Main FPC connect fail
Change Main FPC connect
Receiver connector
Ear phone connector

Q4202 L2 Service Manual
Moto issue
Change SUB
Main FPC fail
Change Main FPC
Main PCBA issue
Change main PCBA/Refer to L3 repair
18: Speaker not working
NO.
Description
Reason
Solution
1
Noise/Crack
Speaker with dust
Clean speaker
Assemble issue
Re-assemble it well
Speaker fail
Change speaker
2
Volume low
The volume to shut down
Press V +, transferred to the suitable volume
Speaker fail
Change speaker
PCBA fail
Change PCBA/Refer to L3 repair
3
No volume
The volume to shut down
Press V +, transferred to the suitable volume
Software issue
Update software
Speaker fail
Change speaker
Main FPC
connect
Mic

Q4202 L2 Service Manual
Main FPC fail
Change main FPC
Sub PCBA issue
Change sub PCBA
Main PCBA fail
Change main PCBA/Refer to L3 repair
Inspect the touching point. If it is broken or deformed, change a new one.
19：Sim Related Issues
NO.
Description
Reason
Solution
1
Sim Related Issues
Software issue
Update Software
SIM card pin Virtual welding
With the soldering iron repair welding pin
SIM card fail
Change SIM card
PCBA fail
Change PCBA/Refer to L3 repair
21：Memory Card Related Issues
NO.
Description
Reason
Solution
1
T card Related
Issues
Software issue
Update Software
T card pin Virtual welding
With the soldering iron repair welding pin
TF card fail
Change TF card
Speaker connect

Q4202 L2 Service Manual
Main PCBA fail
Change main PCBA/Refer to L3 repair
Thanks
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